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Diffstat (limited to 'fs/file.c')
-rw-r--r--fs/file.c147
1 files changed, 59 insertions, 88 deletions
diff --git a/fs/file.c b/fs/file.c
index 4a78f981557..66923fe3176 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -25,7 +25,10 @@
int sysctl_nr_open __read_mostly = 1024*1024;
int sysctl_nr_open_min = BITS_PER_LONG;
-int sysctl_nr_open_max = 1024 * 1024; /* raised later */
+/* our max() is unusable in constant expressions ;-/ */
+#define __const_max(x, y) ((x) < (y) ? (x) : (y))
+int sysctl_nr_open_max = __const_max(INT_MAX, ~(size_t)0/sizeof(void *)) &
+ -BITS_PER_LONG;
static void *alloc_fdmem(size_t size)
{
@@ -34,22 +37,17 @@ static void *alloc_fdmem(size_t size)
* vmalloc() if the allocation size will be considered "large" by the VM.
*/
if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) {
- void *data = kmalloc(size, GFP_KERNEL|__GFP_NOWARN);
+ void *data = kmalloc(size, GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY);
if (data != NULL)
return data;
}
return vmalloc(size);
}
-static void free_fdmem(void *ptr)
-{
- is_vmalloc_addr(ptr) ? vfree(ptr) : kfree(ptr);
-}
-
static void __free_fdtable(struct fdtable *fdt)
{
- free_fdmem(fdt->fd);
- free_fdmem(fdt->open_fds);
+ kvfree(fdt->fd);
+ kvfree(fdt->open_fds);
kfree(fdt);
}
@@ -127,7 +125,7 @@ static struct fdtable * alloc_fdtable(unsigned int nr)
return fdt;
out_arr:
- free_fdmem(fdt->fd);
+ kvfree(fdt->fd);
out_fdt:
kfree(fdt);
out:
@@ -348,21 +346,16 @@ out:
return NULL;
}
-static void close_files(struct files_struct * files)
+static struct fdtable *close_files(struct files_struct * files)
{
- int i, j;
- struct fdtable *fdt;
-
- j = 0;
-
/*
* It is safe to dereference the fd table without RCU or
* ->file_lock because this is the last reference to the
- * files structure. But use RCU to shut RCU-lockdep up.
+ * files structure.
*/
- rcu_read_lock();
- fdt = files_fdtable(files);
- rcu_read_unlock();
+ struct fdtable *fdt = rcu_dereference_raw(files->fdt);
+ int i, j = 0;
+
for (;;) {
unsigned long set;
i = j * BITS_PER_LONG;
@@ -381,6 +374,8 @@ static void close_files(struct files_struct * files)
set >>= 1;
}
}
+
+ return fdt;
}
struct files_struct *get_files_struct(struct task_struct *task)
@@ -398,14 +393,9 @@ struct files_struct *get_files_struct(struct task_struct *task)
void put_files_struct(struct files_struct *files)
{
- struct fdtable *fdt;
-
if (atomic_dec_and_test(&files->count)) {
- close_files(files);
- /* not really needed, since nobody can see us */
- rcu_read_lock();
- fdt = files_fdtable(files);
- rcu_read_unlock();
+ struct fdtable *fdt = close_files(files);
+
/* free the arrays if they are not embedded */
if (fdt != &files->fdtab)
__free_fdtable(fdt);
@@ -437,12 +427,6 @@ void exit_files(struct task_struct *tsk)
}
}
-void __init files_defer_init(void)
-{
- sysctl_nr_open_max = min((size_t)INT_MAX, ~(size_t)0/sizeof(void *)) &
- -BITS_PER_LONG;
-}
-
struct files_struct init_files = {
.count = ATOMIC_INIT(1),
.fdt = &init_files.fdtab,
@@ -505,7 +489,7 @@ repeat:
error = fd;
#if 1
/* Sanity check */
- if (rcu_dereference_raw(fdt->fd[fd]) != NULL) {
+ if (rcu_access_pointer(fdt->fd[fd]) != NULL) {
printk(KERN_WARNING "alloc_fd: slot %d not NULL!\n", fd);
rcu_assign_pointer(fdt->fd[fd], NULL);
}
@@ -645,16 +629,16 @@ void do_close_on_exec(struct files_struct *files)
spin_unlock(&files->file_lock);
}
-struct file *fget(unsigned int fd)
+static struct file *__fget(unsigned int fd, fmode_t mask)
{
- struct file *file;
struct files_struct *files = current->files;
+ struct file *file;
rcu_read_lock();
file = fcheck_files(files, fd);
if (file) {
/* File object ref couldn't be taken */
- if (file->f_mode & FMODE_PATH ||
+ if ((file->f_mode & mask) ||
!atomic_long_inc_not_zero(&file->f_count))
file = NULL;
}
@@ -663,25 +647,16 @@ struct file *fget(unsigned int fd)
return file;
}
+struct file *fget(unsigned int fd)
+{
+ return __fget(fd, FMODE_PATH);
+}
EXPORT_SYMBOL(fget);
struct file *fget_raw(unsigned int fd)
{
- struct file *file;
- struct files_struct *files = current->files;
-
- rcu_read_lock();
- file = fcheck_files(files, fd);
- if (file) {
- /* File object ref couldn't be taken */
- if (!atomic_long_inc_not_zero(&file->f_count))
- file = NULL;
- }
- rcu_read_unlock();
-
- return file;
+ return __fget(fd, 0);
}
-
EXPORT_SYMBOL(fget_raw);
/*
@@ -700,58 +675,54 @@ EXPORT_SYMBOL(fget_raw);
* The fput_needed flag returned by fget_light should be passed to the
* corresponding fput_light.
*/
-struct file *fget_light(unsigned int fd, int *fput_needed)
+static unsigned long __fget_light(unsigned int fd, fmode_t mask)
{
- struct file *file;
struct files_struct *files = current->files;
+ struct file *file;
- *fput_needed = 0;
if (atomic_read(&files->count) == 1) {
- file = fcheck_files(files, fd);
- if (file && (file->f_mode & FMODE_PATH))
- file = NULL;
+ file = __fcheck_files(files, fd);
+ if (!file || unlikely(file->f_mode & mask))
+ return 0;
+ return (unsigned long)file;
} else {
- rcu_read_lock();
- file = fcheck_files(files, fd);
- if (file) {
- if (!(file->f_mode & FMODE_PATH) &&
- atomic_long_inc_not_zero(&file->f_count))
- *fput_needed = 1;
- else
- /* Didn't get the reference, someone's freed */
- file = NULL;
- }
- rcu_read_unlock();
+ file = __fget(fd, mask);
+ if (!file)
+ return 0;
+ return FDPUT_FPUT | (unsigned long)file;
}
+}
+unsigned long __fdget(unsigned int fd)
+{
+ return __fget_light(fd, FMODE_PATH);
+}
+EXPORT_SYMBOL(__fdget);
- return file;
+unsigned long __fdget_raw(unsigned int fd)
+{
+ return __fget_light(fd, 0);
}
-EXPORT_SYMBOL(fget_light);
-struct file *fget_raw_light(unsigned int fd, int *fput_needed)
+unsigned long __fdget_pos(unsigned int fd)
{
- struct file *file;
- struct files_struct *files = current->files;
+ unsigned long v = __fdget(fd);
+ struct file *file = (struct file *)(v & ~3);
- *fput_needed = 0;
- if (atomic_read(&files->count) == 1) {
- file = fcheck_files(files, fd);
- } else {
- rcu_read_lock();
- file = fcheck_files(files, fd);
- if (file) {
- if (atomic_long_inc_not_zero(&file->f_count))
- *fput_needed = 1;
- else
- /* Didn't get the reference, someone's freed */
- file = NULL;
+ if (file && (file->f_mode & FMODE_ATOMIC_POS)) {
+ if (file_count(file) > 1) {
+ v |= FDPUT_POS_UNLOCK;
+ mutex_lock(&file->f_pos_lock);
}
- rcu_read_unlock();
}
-
- return file;
+ return v;
}
+/*
+ * We only lock f_pos if we have threads or if the file might be
+ * shared with another process. In both cases we'll have an elevated
+ * file count (done either by fdget() or by fork()).
+ */
+
void set_close_on_exec(unsigned int fd, int flag)
{
struct files_struct *files = current->files;
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-04 01:26:36 +0000